Calcium-activated neutral protease (CANP), cathepsin B and cathepsin L, each of which belongs to cysteine proteases, are considered to be associated with the decomposition of muscular structure protein in malignant muscular atrophy diseases such as muscular dystrophy and distal myopathy.
Some epoxysuccinic acid derivatives such as N-(L-3-trans-carboxyoxirane-2-carbonyl)-L-leucylagmatine
[Agric. Biol. Chem., vol. 42, pp. 523-528 (1978)], epoxysuccinyl dipeptide derivatives (U.K. Patent No. 2,046,730) and the like have been heretofore known as the compound inhibiting several thiol proteases. However, no epoxysuccinic acid derivatives inhibiting specifically only one of the cysteine proteases have been known.
As a result of the earnest research to compounds having an epoxy ring, the present inventors have found the compounds inhibiting cathepsin B ally unlike the known compounds, and have accomplished the present invention.